Sherman's Tube Amplifier Hobby

DIY High-Fidelity Audio Amplifiers (Hi-Fi)

Vacuum Tube Power Amplifiers, hand crafted, based on the Classics. My curiosity of listening to how they performed and how the different tubes operated inspired and motivated Me to build, order the parts and create. Yes, I do have a few of my own hand drawn schematics accumulated over the decades, these will be my clean slate production designs in the making. I do plan to open a new web page and start the builds of My new designs. But these Amps below, are 23 years of "warm-ups" and also discovery. Kits are not my favorite activity, but in High School & College, Kits were just fine. Building Kits in my humble opinion, is like "paint by numbers", good training for soldering/wiring skills. Yet Kits, are not preparing anyone to actually create a Tube Amp from scratch. Doing scratch Tube Amps by hand, is something rather sobering, as it challenges and also defeats. Unless one has the money to invest in special tools, building kits is the best manner to make Tube Amps at home and enjoy saving money, while making it yourself. If you cannot change a Car Battery, learn that first, and the reason why the order of the connections is critical. This exercise will help You to understand DC and Safety, both critical skills for Tube Amps.

DIY Tube Amplifier Gallery


Mullard 5-20                                 Dynaco MK3

Push-Pull EL34/6CA7                    Push-Pull KT88/6550

Audio Note 2.6K                                 James 2.5K

Version 1                                        Version 2

Single Ended 2A3 NFB**              Single Ended 2A3 NFB**

Dynaco SA-35*                                  Olson Amplifier (SR61 Aurora)

Push-Pull EL84/6BQ5                             Push-Pull 6F6S NFB**

My own 5AR4/GZ34 Tube rectified version with a Hammond Transformer

My version sounds superior to the original budget conscious ST-35 that used rectifier Diodes

(SA-35* = ShermanAudio-35)

(NFB** = No Feedback)

So there is always something on my workbench

By learning & hearing something new, with each build, my ultimate goal after 23 years has been that I am still learning. My curiosity has not yet waned. My path has pushed me towards seeking new challenges. To Me this is the best result of self motivation.  I always seem to want to know more, and when I cannot find answers to the questions I have I search online, and talk to other enthusiasts, even sometimes, through experts in person at Audio Shows. Sharing insights with open minded designers, makes this worth the enjoyment of Music through artisanal equipment, the simplicity of Tube Circuits makes them ideal for tweaking, and this is how we learn, by doing, and thinking about things and modifying our own builds, rather than guessing on someone elses hard work. I do not enjoy modifying other peoples work as I do not feel that changing what was already done and optimized, is not a good thing to do. Some love changing parts, and that is fine with Me.

DIY Musical Instrument Amplifier (M.I.)

First of many Guitar Vacuum Tube Power Amplifiers

Yes, I do plan to DIY a few "Combo Amps"

This Guitar amp was a re-hash of what I learned from the SR-91 Aurora Amplifier. The amalgam of Tube Amp knowledge, built up over the last decades motivated this Guitar Amp build, based on the Olson Amplifier Cathode Bias with a 12AX7 Preamp-Tone Control section added. The Push Pull 6F6S have a 'touch' of Global Feedback, so the Musician can cut loose on Guitar, and not drive the Amp into unstable conditions. Control Theory teaches Circuit Stability and is a very interesting subject, with empirical applications of Closed Loop Feedback stability. Negative Feedback is a positive thing, so don't allow others to poison your journey. Running a Car without Shock Absorbers might work for some roads, but we all understand how damping helps keep us safe and in control. Feedback in circuits, is just one technique to stabilize a system that otherwise would become unstable without it. Ask any Single Ended NFB Audio lover what happens to the music when they push the amplifier hard, it distorts beyond what our ears can tolerate. Push Pull Amplifiers are more complex, and hence require some level of feedback to achieve stability. Push Pull amplifiers can be empirically designed to safely operate without feedback, and this is where art meets science. But Feedback not only improves frequency response, but protects your speakers, especially tweeters.

What might be next

in my new Musical Instrument Amplifier quest?

A Bass Guitar Amplifier using out of production Magnetek-Triad S-42A, sounds interesting. I also have a hand drawn, 10 Watt E80L/6227 Guitar Amp to consider. Both amps concepts are now planned for 2026. But, before them, my Transcendent Sound Cathode Follower SE Hi-Fi amplifier project is next up, after I complete the CAT SL-1 clone. After years of delays and procrastination, due to professional priorities. I ran into trouble last night, and I describe this in my Hand Crafted section of the CAT SL-1 clone build. Honesty and Success, with Failure is how this Hobby operates, not always rose colored. Making mistakes, keeps Me sharp and Cautious. Developing good Workbench manners is essential to reducing errors. My biggest lesson, stop when tired. That is when big mistakes always happen. Fatigue clouds our senses, we have to learn to stop, even though our minds want to keep going towards the ultimate goal. There is nothing like the thrill of listening to a new creation sound, for the very first time, after month's of assembly. When the speakers start to play, my Heart skips a few beats.

Our country needs prayer

Thank you for your time

There just may be a 'glowingly-warm' Tube Amp

somewhere in your present or future, it's just a matter of Time.